Method of making calcium carbid.



H. L. HARTENSTEIN. METHOD OF MAKING CALCIUM GABBID.

APPLICATION rum) NOV. so, 1906. I g: r"

Patented Aug. 9,1910.

2 sums-slum 1.

H. L. HARTENSTEIN. 'METHOD OF MAKING CALCIUM GARBID.

APPLICATION FILED NOV. 30, 1906.

Patented Aug. 9,-1910.

2 SHEETSSHEET 2.

, current.

UNITED STATES PATENT OFFICE.

HERMAN L. HARTENSTEIN, OF CONSTANTINE, MICHIGAN, ASSIGNOR, BY MESNEAS-SIGNMENTS, TO CONTINENTAL INVESTMENT COMPANY, OF DULUTH, MINNESOTA,

A CORPORATION OF MINNESOTA.

METHOD OF MAKING CALCIUM CARBID.

To all whom it may concern:

Be it known that I, IIERMAN L. HARTEN- STEIN, a citizen of the UnitedStates, residing at Constantine, in the county of St. Joseph and Stateof Michigan, have invented certain new and useful Improvements inMethodsof, Making Calcium Carbid, whereof the following is a full, clear, andexact specification.

This invention relates to methods of mak- I ing calcium carbid; and itcomprises a process of producing calcium carbid wherein the wastecombustible gases and heat ofthe carbid furnace are utilized inpreparing the materials to be introduced theremto; all as more fullyhereinafter set forth and as claimed.

In the manufacture of calcium carbid in the electric furnace, theoperation is a purely thermal one, the electric current serving merelyas a heating agent. Substantially the action may be said to be thereduction of calcium o xid by carbon to form calcium and carbon monoxidand the subsequent union of the calcium with carbon to form the carbid;all of which reactions are strongly endothermic, absorbing many heatunits. Thedegree of temperature in the operation must also be very high.It is usual to feed the electric furnace with lime rather than limestonesincethe decomposition of limestone to form lime is also an endothermicreaction and if it takes place in an electricfurnace much additionalheat must be furnished, requiring the use of additional The more heatcan be economized in the whole operation, of course the less is thedemand on the current for heating.

The present invention is more particularly concerned with methods ofutilizing and saving the heat from the electric furnace, both that heatwhich is, so to speak rendered latent in the formation of carboninonoxid and that which goes off with the gases as sensible heat. Forthis purpose the hot combustible gas coming from the electric furnacesis directly burned in contact with limestone or other form of calciumcarbonate to form lime to be used in such electric furnace. The hotgases coming from the furnace are burned directly 1n contact with thematerial to be calcined, freeing it of Specification of Letters Patent.

Application filed November 30, 1906. Serial No. 345,607.

Patented Aug. 9, 1910.

carbon dioxid and heating it up and the heated calcined material isdelivered to the electric furnace. Both the sensible heat and the heatof combustion are utilized. The limestone is best treated in thepowdered or granulated form in an inclined rotary kiln, where it istreated in the form of a tumbling, agitated, relatively thin travelingstream. In order to supplement the heat derived from the kiln gases, Iordinarily employ producer gas coming hot from a suitable producer. Thishas the additional function of somewhat lengthening the flame which thegas coming from the electric fur.

nace would ordinarily give. This gas being formed, in the absence of airis not diluted by nitrogen and is rich in carbon monoxid. A' hot flameof strong carbon monoxid gas is apt to be short while the needs of therotating kiln require a flame as long as may be. The relatively poor gasfrom the gas produ cer serves to lengthen the flame of the purer gascoming from the electric furnace. I preferably employ the waste heatfrom the rotary kiln in order to heat the air required for combustiontherein, and I may also utilize a portion of this waste heat in heatingthe coke orcarbon going into the electric furnace to produce calciumcarbid.

In the accompanying drawings I have illustrated more or lessdiagrammatically one of the many embodiments of apparatus elementspossible for use within the described process. To .this apparatus I makeno claim herein, it forming the subject matter of my Patent 888,610,granted May 26, 1908, upon my co-pending application Serial No. 345,751.

In this showing :Figure 1 is a diagrammatic View, partly in sideelevation and partly in section; Fig. 2 is an enlarged detailsectionalview, partly broken away and partly sectioned, of a conveyerchamber with a conveyer. therein, and with an air-heating jacket; Fig. 3is a plan view of the apparatus illustrated in Fig. 1, with some of theupper parts omitted for the sake of clearness; and Fig. 4 is an enlargeddetail vertical longitudinal section of one of the calcining furnaces.

In the showlng, elements 1 and 2 are a pair of slmllar rotary kilns. Asingle kiln may be used or the number may be more the end of the kiln.

than 2, but two form a convenient arrangement. Each of these kilns is ofthe ordinary form save as regards the hood at the mouth. .They may beplaced in motion by suitable means, such as the encircling gear 3 andpinion 4, driven by shaft 6 from any suitable" source of power. The kilnmay be operated in the usual manner by bearing bands 7 and 8 on suitablepillows 9 and 10. The kilns are respectively provided with bins orhoppers 11 and 12 for the continuous feed of raw material. From the binsthe limestone may be taken into the kiln by any suitable means, as forinstance, the

screw conveyer 13, feeding another conveyer 14 which discharges materialdirectly into At the lower end of the kiln is provided a stationary hood-or combustion chamber 15 mounted on suitable supports 16.- Combustiblegas may be supplied it from gas producer 17 by the usual connect-ions18, 19-and 20. As shown, each kiln is provided with its own gasproducer. A further supply of combustible gas furnished to eachcombustion chamber by connections hereinafter specified. Returning tothe kiln, at its lower end the calcined lime discharges through aperture21- formed in a casing '22 located between the .combustion chamber andthe end of the kiln and carried on truck 23. These elements are fittedtogether to form as close a joint as may be between the combustionchamber, the housing and the end of the kiln.

The interior of the housing should be formed so'that the bottom thereofwill be substantially level or slightly-inwardly and' combustionchamber.

- lation of-dimensions, the hottest point in.

backwardly inclined over the bot-tom'of the combustion chamber so as toavoid any tend-,

ency of the calcined material to-pass beyond the discharge aperture 21and enter the The length of the combustion chamber is so proportionedwith respect to the strength of the draft passing therethroug h andtothe character and vol-" ume of the heatin gas consumed that the I pointof most per ect combustion will take place substantially at a pointabove the discharge aperture. By producing this correthe flame will beimmediately above the calcined limeat the point of discharge and thelime consequently will be extremely hot, and it will be suitedfor,delivery to the, electric furnace. Other things being equal, thehotter the materials are when delivered to the electric, furna'ce inmaking calcium carbid 'the less is the quantity of current required.

Following the'hot calcined lime from the kiln, it falls through hopper24 past a controlling gate .orvalve 25, into a weighing machine 26. Fromthe weighing machine it goes into a mixer 27. The coke or other car 66bon necessary for the charge is-discharged with the supply pipes leadingfrom the gas producers to the combustion chambers, so that thehot richgas from the electric furnaces can be commingled. in any desiredproportion with the poorer gas from the gas producers. Returning now tothe kiln, it will be noted that the upper end enters a housing or dustchamber 37 provided with an uptake or stack 38, the latter allowing theproducts of portion thereof to be discharged into the atmosphere ifdesired. The housing is also provided with an outlet 39, communicatingwith a manifold drum 40, common .to the two kilns. From this drum hotgases may be led' by a pipe or flue 41 to and through ahorizontal-chamber 42 to a. stack or uptake t3. This horizontal chamberis inclosed and spaced away from a surrounding casing 4H,.serving as anair jacket. This air jacket as shown opens freely to the atmosphere atthe end next the main stack of the kiln and atthe other end communicateswith a discharge flue 45- provided with a combustion or any givenprosuitable fan or exhauster 46. This fan 'se'rvcsto pass 'the airheated in\t'he' jacket through pipes/t7 and 48 to-theburners of thecombustion chambers. When it is desired-to pass hot waste gases from thekilns through the horizontal chamber, the main stack of the kiln may bepartially closed.

bya damper or valve 49. Similar dampers 50 and 51 may be employed inshutting off part of the waste heat from-the drum.

.' The horizontal chamber so far asv described has served merely as anair heating means but it may also be used as a means for affording heatto the carbon to be used'in the electric furnace. While it ispractically impossible to heat coke or other carbonto any very hightemperature by a flame or products of combustion, since above a certaintemperature carbon dioxid reacts with carbon to 'form carbon monoxid(the principle upon which the gas producer is based) yet heat short ofthis point may be imparted to the coke by the waste gases from the kiln.After having passed from the calcining limestone,,the products ofcombustion are reduced in temperature below the danger point. As shown,within the horizontal chamberv moves an endless conveyer 52 which may beof any suitable construction being, for instance, provided with thepockets 53 shown. plied from any suitable source as by conveyer 54 fromdischarge spout 55.

In the operation of the described apparatus, it will be seen that theelectric furnaces are supplied with highly heated calcined lime andcarbon which has separately been heated as highly as possible. In theelectric furnace the hot lime and carbon are brought to the calciumcarbid forming temperature by means of the electriccurrent. Obviously,the more heat can be taken into the furnace with the raw materials theless is the heating duty imposed on the electric current. In theformation of calcium carbid, intensely hot carbon monoxid is formed andthis carbon monoxid is directly led into the base of a rotary calciningkiln Where it is burned with heated air to calcine limestone and furnishhot lime for delivery to the electric furnace, the flame conditionswithin the rotary kiln being in a measure regulated and controlled bythe supply of producer gas from an ordinary producer. The waste heatfrom the calcining kiln is in part recovered as the sensible heat of airused to produce combustion in the kiln and in part is recovered assensible heat of coke or other carbon to be fed into the electricfurnace.

With the described arrangement not only is a maximum economy of heat andenergy secured but also the calcined lime being directly delivered tothe electric furnaces,

has no opportunity of cooling or suifering deterioration by theabsorption of carbon dioxid and moisture from the air,

What I claim is 1. In the manufacture of calcium carbid, the methodwhich comprises heating lime and carbonaceous material in the presenceof each other, but excluded from oxygen, to producecalciumcarbid andcombustible gas,

removing the combustible gas, burning said gas with air to form'a flame,calcining calcium carbonate with said flame to produce lime and heatingsaid lime with carbonaceous material to produce carbid.

2. In the manufacture of calcium carbid, the method which comprisesheating lime and carbonaceous material in the presence of each other toproduce calcium carbid and combustible gas, mixing the resultant gaswith air, burning the same in the presence of calcium carbonate toproduce lime, preheating carbonaceous material with the resultantproducts of combustion and mixing the heated material with the lime.

3. In the manufacture of calcium carbid, the method which consists insubjecting calcium carbonate to the calcining influence of,-

burning fluid fuel elements, moving the carbonate through the saidelements in the op- This conveyer .may be supposite direction to that oftheir line of travel, removing the resultant lime from said elements atthe point of most perfect combustion therein, mixing with the hot limethus obtained, while in its highly heated condition, a quantity-ofcarbonaceous material, and subsequently heating the mixture to producecalcium carbid. I

4. In the manufacture of calcium carbid, the method which comprisesheating lime and carbonaceous material. in the presence of each other,but excluded from oxygen, to produce calcium carbid and combustible gas,mixing the resultant gas with air, completely burning the same inthe-presence of calcium carbonate to, produce lime, sultant lime whilestill heated above atmospheric temperature with carbonaceous material,and finally heating the mixture of lime and carbonaceous material toproduce calcium carbid.

\ 5. In the manufacture of calcium carbid, the method which comprisesheating lime and carbonaceous material in the presence of each other toproduce calcium carbid and combustible gas, removin and burning theresultant gas with air to form a flame, com pletely burning said flamein the presence of and in direct contact with calcium carbonate toproduce lime and subjecting the lime with in admixture of carbon to afusing degree of eat.

6. In the manufacture of calcium carbid, the method which comprisessubjecting calcium carbonate to the calcining influence of burning fuelelements, removing the resultant limefrom the influence of said elementsat the point where the most perfect combustion occurs, mixing with thehot lime thus obtained, .while in its highly heated condition, aquantity of previously heated carbonaceous material, and subsequentlyfusing the mixture to produce calcium carbid.

7. In the manufacture of calcium carbid,

mixing the rethe method which comprises subjecting cal- 3 passing hotcombustion gases over its surl face and agitating the material to exposefresh surfaces, and electrically heating the preheated material to therequired temperature, as set forth.

9. The

process of smelting divided refrac- 7 tory compounds, which consists inpreheating a supported body of the material by passing hot gases overits surface and rotating the material to expose fresh surfaces, andelectrically heating the preheated material to the required temperature,as set forth.

10. The process of smelting divided refractory compounds, which consistsin preheating a supported body of the material by passing hot gases overits surface and agitating the material to expose fresh surfaces,delivering the preheated -material to the smelting furnace andelectrically heating it to the required temperature, and feeding freshmaterial into the preheated atmosphere, as setforth.

11. The process of smelting divided refractory material, which consistsin preheating a supported body of the material by passing hot gases overits surface and rotating the material to expose fresh surfaces,

delivering the preheated material to the smelting furnace andelectrically heating it to the required temperature, and feeding freshmaterial into the preheating atmosphere, as set forth.

12. The process of smelting divided refractory compounds, whichconsistsin preheating a supported body of material by passing hot combustiongases overits surface and agitating the material to expose ture of limeand carbon in an electrical furnace to produce calcium carbid andcombustible gas, removing and completely burning the combustible gas inproximity to calcium carbonate to produce lime and translong ferring thehot lime to said furnace for conversion into carbid.

15. In the manufacture of calcium carbid, the process Which comprisesremoving the combustible gases from an electrically heated carbidfurnace, completely burning such gases as a flame in proximity tocalcium carbonate to produce hot lime, mixing the hot lime with carbonand transferring the mixture to said furnace to aid in producing carbidand further quantities of combustible 16. In the manufacture of calciumcarbid, the process which comprises calcining calcium carbonate in atumbling, relatively thin traveling stream with the aid of a completelyburning flame of combustible gas from an electrically heated calciumcarbid furnace, mixing the calcines with carbon and delivering themixture into such furnace.

17. In the manufacture of calcium carbid, the process which comprisescalcining calcium carbonate in a tumbling, relatively thin travelingstream and smelting'the resultant calcines in an electrically heatedcarbid furnace, the combustible gases from said furnace being brought toa state of complete combustion and employed as a flame in proximity tosaid stream.

18. I11 the manufacture of calcium carbid, the process which comprisescalcining calcium carbonate with a flame of a burning mixture ofcarbid-furnace gases and producer gas in proportions adjusted to form a19. In the manufacture of calcium carbid, the process which comprisescalcining calcium carbonate in a-tumbling, relatively thin travelingstream with a flame of a burning mixture of carbid-furnace gases andproducer gas. i

In testimony whereof I have signed my name to this specification, in,the presence of two subscribing witnesses, on this 27th day of NovemberA. D. 1906.

HERMAN L. HARTENSTEIN.

I Witnesses:

FRANCIS A. HOPKINS CHAS. H. SEEM.

